Color blindness is a form of color blindness, predominantly a congenital visual pathology, in which the patient cannot distinguish the colors of surrounding objects.
We feel all the richness of shades due to the presence of light-sensitive cells in the retina.
With color blindness, the patient may not notice lush green grass, endless blue sky, red strawberries, etc. In the rarest cases, the patient can see the world as if in a black and white movie. People who cannot see colors are called colorblind.
Medical history
For the first time, inadequate color perception was studied and described by the English scientist John Dalton. He himself was a carrier of such a pathology and did not suspect about it until he was 26 years old. Dalton could not distinguish red from green. In his case, the disorder was caused by a genetic predisposition, since the scientist’s sister and two brothers had the same symptom. In 1794, the researcher published a work on color vision disorders and introduced the concept of “color blindness,” naming the disease in his honor.
How does the human eye distinguish colors?
The generally accepted theory states that the retina contains light-sensitive receptors containing specific nerve cells - cones and rods. Depending on the color-sensitive pigment contained in the cones, these cells are divided into 3 types: those that perceive red, blue and green. This is the basis of the spectrum, all other colors and shades are obtained by mixing these three.
The rods are responsible for black-and-white vision; if the cones are completely non-functional (in complete color blindness), a person sees the outlines of objects due to the receptors of the rods.
Cones respond to light reflected from the surface of objects. The angle of reflection and wavelength determine the green, red or blue spectrum. The signal from the receptors enters the brain, so a person perceives the color of surrounding objects.
Pathology appears if one or more pigments responsible for the normal functioning of visual receptors are missing. Sometimes the retina has all the necessary pigments, but they are not enough for correct color perception.
What is color blindness
When even one visual pigment is missing in the retina, a person is able to distinguish only two shades. Given the statistics, this disease mainly affects men. Female color blindness is very rare.
Basically, this pathology is diagnosed as abnormal trichromacy. Usually the disease passes from parents to children. Distant relatives do not genetically transmit this pathology. Women very rarely encounter this disease. Mostly men face it. The disease has two forms: partial and complete. Pathology is diagnosed by the following types:
- achromatopsia (full form);
- deuteranomaly;
- tritanopia;
- protanopia.
It is worth noting that with a partial form of the disease, it is still possible to lead a normal life. The complete lack of color distinction makes a person's life limited.
Causes of color blindness
There are 2 main causes of color blindness: heredity and acquired dysfunction of color receptors. Initially, only the hereditary form was known, but later, with the development of ophthalmology, it became clear that injuries to the eyeball, certain diseases, and even medications could disrupt the perception of colors.
Hereditary color blindness
Hereditary color blindness is associated with a defect in the X chromosome, which contains the genes responsible for the color-sensitive pigment in the cones in the retina.
In cases where color blindness is a hereditary pathology, color perception is equally impaired in both eyes. The disorder does not get worse with age, but it does not go away either.
The gene for color blindness can be passed on through generations, manifesting itself in grandchildren or great-grandchildren. To make sure there is no genetic predisposition to impaired color vision, you can take a DNA test. This method is applicable in cases where conventional visual tests cannot be used, for example, for newborns and children in the first years of life.
Acquired color blindness
Different types of color blindness result from:
- eye diseases affecting the retina and optic nerve;
- complications in diseases of the nervous system;
- macular degeneration due to diabetes;
- mechanical injury to the eyeball;
- damage to the retina by ultraviolet radiation;
- pathological changes associated with age;
- taking certain potent medications.
Often acquired color vision deficiency manifests itself in only one eye if it is caused by injury or illness. This type of color blindness progresses over time, but in some cases it is curable. Among acquired color perception disorders, the most often observed is a failure in the blue part of the spectrum, when a person cannot distinguish between shades of yellow and blue.
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Description
Color blindness is most often a hereditary disease in which a person cannot distinguish one or more colors.
It occurs in both women and men. Types of color blindness:
- protanopia - in which a person does not distinguish green shades from red ones;
- deuteranopia - a sick person does not distinguish green from blue;
- tritanopia – visual impairment in the blue-violet part of the spectrum. A person sees only red and green shades;
- trichromasia - a person distinguishes three primary colors. Moreover, this condition may be completely normal and not be characterized as color blindness;
- achromatopsia – characterized by a complete absence of color sensations.
Also, color blindness can be acquired or congenital. In some cases, a person does not even suspect that he has problems with color perception. You can find out about this only after a visit to an ophthalmologist, who is involved in diagnosis and treatment.
Color blindness is an autosomal recessive disorder. In many cases it is inherited from mother to son.
There is also the concept of emotional color blindness, which means the lack of adequate separation of all the nuances of a person’s emotional state.
Protanopia – red-green color blindness
This type of color blindness occurs in 7-8% of men and 0.2-0.5% of women. This disease is characterized by a lack of normal perception of the colors green, red and blue. Most often, such color blindness is inherited. Treatment for this form of the disease is unsuccessful. In this case, the person has a color blindness gene that causes this defect.
Protanopia is associated with the absence of certain cones in the retina, which are necessary for normal perception of the orange and red parts of the spectrum. In this case, a sick person will perceive the yellow-green color as orange, and the purple color for him will be no different from blue. However, it will separate the green tint from the blue color, and the rich red from the green.
Deuteranopia – human color blindness
Vision in the presence of color blindness of this type is impaired in most cases from birth. Deuteranopia affects about 1% of the population.
If you show a sick person pictures where purple, yellow-green, blue-green tones predominate, he will not be able to see and interpret them correctly.
Green and red color blindness is caused by the absence of a special pigment on the retina - chlorolab, which is responsible for the perception of this region of the spectrum. At the same time, a patient with deuteranopia can clearly distinguish the color green from red and violet.
Tritanopia is a type of color blindness
One of the types of color blindness, which implies the lack of adequate color perception of a certain part of the spectrum. In most cases, this disease is congenital in nature and is extremely rare.
Women suffer from this type of color blindness in the same numbers as men. This is due to the fact that the cause of this disease is a mutation in chromosome 7, which is equally likely to occur in both sexes.
Color blindness in this type of color blindness occurs in the areas of blue-yellow, violet and red hues.
Achromatopsia - complete color blindness
Achromatopsia and color blindness - what is the difference? Achromatopsia is characterized by a complete lack of color vision. Sick people cannot distinguish any colors. They see everything as gray.
There are the following types of achromatopsia:
- rod - there are no cones, which are necessary for the normal perception of different colors. In this case, all light waves hitting the retina are perceived as a gray tint;
- cone - characterized by the perception of all colors in one tone.
Colorblind people who suffer from this type of colorblindness are very rare, and most often this problem is congenital. This defect is also accompanied by nystagmus and photophobia.
Trichromasia - rainbow color blindness
This type of color blindness is characterized by the presence of some difficulties in perceiving individual shades, while the patient sees the predominant number of colors well.
The following forms of color blindness trichromasia are distinguished:
- A – the perception of green and red shades is almost completely absent;
- B – a serious disorder in which the patient distinguishes colors with great difficulty;
- C – minor anomaly that does not cause significant discomfort.
If there is some defect in the perception of certain colors, other shades, on the contrary, may become more pronounced.
Who suffers from color blindness more – women or men?
The recessive gene for color blindness is in all cases transmitted from the carrier mother to the son. This is due to defects in the X chromosome. In this case, color blindness is gender-linked. Men are most susceptible to this defect.
Inheritance of color blindness occurs through the female line. It appears in most cases in men. According to statistics, 3-7% of strong people suffer from this disease. Color blindness in women occurs only in 0.5% of cases. This is due to the presence of XX chromosomes as opposed to male XY chromosomes. In the weaker sex, the defective X chromosome is compensated by another normal one.
Does colorblindness occur in women? This problem can be congenital if both parents are carriers of defective genes. Therefore, not only men, but also women suffer from color blindness. Especially in cases where the disease appeared during a person’s life. Color blindness is linked to gender only in the case of a hereditary problem.
Is color blindness a recessive or dominant trait?
The genotype of color blindness is determined by the presence or absence of a recessive trait. A woman can be completely healthy, but be a carrier of a defective gene. If a girl's father suffers from color blindness, then there is a high probability that this problem will manifest itself in her son. This is due to the fact that a woman will pass on to her child a recessive trait that she received from her parents.
Hemophilia and color blindness are related because these diseases are passed from mother to son. However, they do not appear in women. A man suffering from color blindness and deafness can reproduce both healthy and diseased offspring, depending on the mother's genotype.
Color blindness in children
The likelihood of having a male child suffering from color blindness is high when the mother is the carrier of the defective gene. When the father is sick, but the other parent is completely healthy, he is not afraid of this disease.
Children's color blindness often causes a lot of concern among parents. This complicates their education, since in kindergarten or school such a problem is perceived as mental retardation.
These children need to be adapted to their environment. It is important to teach your child to distinguish colors and shades that he does not see.
Color blindness and driver's license
Not every country allows a person who is colorblind to obtain a driver's license. In Russia, only since 2014 have people with this problem been allowed to drive vehicles. The only categorical contraindication in this case is achromatopsia.
The driver's color blindness will be an obstacle to obtaining a license in Romania or Turkey. In the European Union, this problem is not a reason for refusal to issue these documents.
Types of color blindness
The classification of types of color blindness (color vision pathologies) is based on which of the primary colors the patient does not see or has difficulty distinguishing.
Protanopia
(from the Greek protos - first, since red is conventionally considered the first color) - impaired ability to see red. This genetic mutation is more common than others. People with protanopia, looking at red objects, see them as brown, dark gray, black, and less often dark green. They perceive green as light gray, yellow or light brown.
Deuteranopia
(from the Greek deuteros - second) - pathology in the green region of the spectrum. Instead of green, a person with deuteranopia sees light orange or pink, and perceives red as brown.
Tritanopia
(from the Greek tritos - third) - allows you to see red and green with all their shades, which replace the blue part of the spectrum. The inability to perceive blue and violet is not the only defect in tritanopia - the pathology affects the functioning of the rods and leads to the absence of twilight vision.
Color blindness can be classified according to the degree of color vision impairment, depending on whether the pigment in the cones is completely absent or its amount is only limited and insufficient for full, bright vision.
Normal perception of primary colors is called trichromacy. A person who can distinguish all colors, but they appear faded and lack sufficient contrast, is diagnosed with abnormal trichromacy. If vision in a certain part of the spectrum is impaired, but not completely absent, the mutation is named according to the color affected: protanomaly, deuteranomaly or tritanomaly.
Dichromasia
assumes that the eye distinguishes two primary colors and does not perceive the third, replacing it with shades of the first two. Within the framework of dichromasy there are protanopia, deuteranopia and tritanopia.
A person with monochromasia
vision distinguishes only one of the primary colors. This mutation is often accompanied by photophobia and nystagmus.
Achromasia
(color blindness) is a rare phenomenon associated with the absence of the pigment responsible for color vision. The world in the eyes of a person with achromasia looks black and white with shades of gray and is completely devoid of other colors.
Sometimes nature compensates for the inability to see one color with a more subtle perception of another. For example, people with protania can see more shades of green than is possible with full trichromatic vision.
Classification
Depending on what colors the patient cannot distinguish, the following types of color blindness are distinguished:
- Protanopia is the inability to perceive the color red. The mutation is most often diagnosed.
- Deuteranopia is green color blindness.
- Tritanopia is the inability to perceive blue or violet colors.
- Monochromacy is the perception of only one color.
- Achromasia is a complete inability to perceive colors (complete color blindness).
- Anomalous trichromasia is a case of decreased activity of red, green or blue pigments.
Color blindness in women
Women are susceptible to hereditary color blindness 20 times less often than men. The statistics are that color blindness in women with impaired color perception occurs in approximately 0.5%, while in men it is 5-8%.
It's all about the set of chromosomes: women have two X chromosomes, so even if one of them carries the color blindness gene, the second compensates for the defect. In this case, the pathology will not manifest itself, but will be passed on to the son or daughter. Men have only one X chromosome, and, accordingly, there is no reserve to replace a gene with a mutation.
A boy will most likely have impaired color perception if one of the mother's X chromosomes contains this pathology. A son is less likely to be born colorblind if only the father has the genetic predisposition. For pathology to manifest itself in a girl, a mother and father with hereditary color blindness are needed. This combination is quite rare.
Acquired color vision deficiency can be equally likely to appear in a man or a woman, since it is not tied to the chromosome.
Can girls be colorblind?
A girl often acts as a carrier of a damaged gene, which she inherited from her father or mother. But a violation in the perception of colors occurs only if both chromosomes are “damaged.” This happens extremely rarely and can happen during consanguineous marriages or an accidental coincidence of a colorblind father with a mother who carries the gene. Color blindness is much more common in men than in the fairer sex.
Adult women may experience a pathology such as false color blindness. Not a single person is immune from this anomaly. It manifests itself with injury to the organ of vision or retina, or damage to the brain. In such cases, only one eye is affected; most often, patients are not able to distinguish shades of the yellow-red spectrum.
Color blindness in children
Congenital color blindness is difficult to diagnose in childhood due to the absence of external clinical symptoms. Many colorblind people learn about their pathology in adulthood completely by accident or during a specialized medical examination. How do you know if a child is color blind?
Watch him carefully while drawing, working with colored paper or plasticine. The reason to check your baby’s color vision is the presence of the gene responsible for color blindness in one of the parents.{banner_gorizontalnyy2}
Impaired color vision, especially if parents do not know about it, complicates the child’s life. Inadequate perception of colors can negatively affect academic performance, relationships in a team, and ultimately, inner peace and self-esteem. Without proper explanation from adults, a generally insignificant pathology creates a lot of problems for the baby.
Caregivers and teachers should be warned about color blindness. This will help to avoid awkward situations with visual materials, and not to use colors and combinations that are inaccessible to the baby’s vision. A child with color vision impairment should sit at a desk that is not exposed to direct sunlight from a window.
The smallest colorblind child must be explained as early as possible that he sees the world differently from other people, but this feature does not make him worse than others.
Difficulties in diagnosing color blindness in children
Why does children's color blindness often escape the attention of parents and teachers? The fact is that a child is able to truly distinguish colors by the age of 3-4 years. While the names of flowers are explained to him from the age of 1.5-2 years. “This cube is blue, and this one is red.” “The grass is green, the dandelions are yellow.” The baby remembers what it calls this or that color and uses the memorized name. How he actually sees what he calls red or green, adults cannot know.
To check color perception, you need to watch a child when he draws from life or tries to convey the surrounding reality through other types of creativity. The easiest way is to ask your child to draw a landscape outside the window, flowers in a vase, or favorite cartoon characters. Based on the results, you can evaluate how adequately he perceives the colors of surrounding objects. For example, a clear sign of color blindness would be replacing red with green or brown. However, such a home test cannot be considered reliable, because there is a risk that the child selected colors based on his own ideas about beauty or guided by imagination.
If your baby systematically replaces one color with another, you should consult an ophthalmologist. Only a doctor can diagnose color blindness based on special tests.
How to determine the presence of a disease?
As a rule, a slight violation of color vision appears randomly, since it does not cause any particular discomfort. In children, color blindness is usually more difficult to identify, since the child gets used to replacing a color with the name of that color, and perceives, for example, a shade of blue as green or red.
Signs of color blindness vary from species to species, but a common feature includes impaired color recognition.
Color blindness test
The most common and effective test for color blindness is performed with polychromatic tables E.B. Rabkina. The method was developed in the mid-twentieth century and remains the most effective today. The main test set includes 26 tables with depicted numbers of different colors; sometimes a set of 48 tables is used if high diagnostic accuracy is needed.
The tables consist of small circles of different sizes.
On a background of circles of one color, numbers, geometric shapes and chains are drawn in circles of another color. A person with full color vision sees contrasting images on the tables. A colorblind person can distinguish colors on some tables, and drawings made in an inaccessible color seem monochrome to him. For accurate diagnosis, special conditions are needed:
- daylight;
- lighting should not be too bright or blinding;
- the light should come from behind the patient;
- You should not put pressure on a person during the test - results under stress can differ greatly from color perception in a state of rest and tranquility.
Each chart is shown at eye height approximately 1 meter from the patient. 5-7 seconds are allotted for one image, then it is removed and the one who takes the test reports what he saw.
To test color vision at home using the Rabkin table, you can use the online table. But you cannot rely on the test results from the screen of a PC or mobile gadget, since it is affected by the brightness and resolution of the monitor. If the test indicates impaired color vision, you need to contact an ophthalmologist to clarify the diagnosis.
In addition to the tables edited by Rabkin, there are tests for color recognition by Ishihara, Stilling and Yustova. They work on the same principle as the test described.
In some cases, the Holmgren method is used to diagnose color blindness, based on the need to distribute skeins of multi-colored yarn into the three main colors of the spectrum.
Color vision impairment can be determined using a spectral method using special equipment. This method is used in situations where the pigment method (based on the patient’s visual perception) does not work. For spectral diagnostics, the Rabkin spectroanamaloscope, Nagel, Girenberg and Ebney apparatuses are used.
Diagnostics
The congenital disease is difficult to diagnose in childhood. Many patients find out that they are color blind only during a physical examination.
Diagnosing childhood color blindness is associated with certain difficulties. This is due to the fact that a child masters colors by about four years of age. But even in this case, he uses memorized data (for example: the sky is blue, strawberries are red). But adults don’t know how he actually sees objects.
The easiest way to diagnose color blindness at home is to invite your child to draw what he sees outside the window. And based on the results, you can see how accurately the baby perceives colors. Colorblindness may be indicated by changing colors (for example, red to brown). This indicates that the child is confusing colors.
The most common and simple test for color blindness is done using Rabkin tables. The set includes 26 different tables. With their help, you can easily diagnose colorblind vision. They have numbers or pictures printed on them in the form of small circles. They are made in different color combinations. A person without color blindness can easily determine what is drawn. A colorblind person will indicate images only of those colors that are accessible to perception.
For an adequate examination you need:
- natural lighting;
- dim light;
- placing a light source behind the patient's back.
The table is shown at eye level at a distance of approximately 1 meter. People with normal vision read all tables.
In addition to determining color blindness using the tabular method, the Holmgren method is used. It is based on the fact that the patient is asked to place skeins of yarn of different colors.
If it is impossible to diagnose color vision disorder using the tabular method, they resort to spectral analysis.
Treatment of color blindness
Congenital color blindness associated with a genetic mutation is incurable. In some cases, color perception can be corrected with professional glasses or lenses. The effectiveness of this approach to solving the problem directly depends on the specific type of pathology.
Acquired vision defects can sometimes be treated. The cause of the pathology is of great importance. Only a qualified ophthalmologist can give a reliable opinion on this matter. Depending on the factor that provoked the disorder, treatment is prescribed. So, if color blindness appeared as a result of the action of medications, their use should be stopped, and there is a possibility that the ability to distinguish colors will be restored.
Treatment of color blindness with folk remedies is impossible!
When the color sensory receptors are affected by cataracts, glaucoma or other eye diseases, it is hoped that after surgery the ability to distinguish colors will return. In case of age-related changes and clouding of the lens of the eye, the loss of color vision is irreversible. Scientists are exploring the possibility of correcting mutations at the gene level, but so far such techniques have not left the laboratory doors.
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How is the disorder diagnosed in girls?
Some types of color blindness (for example, monochromasia) are detected almost immediately after manifestation. But a mild degree of trichromosia can often be diagnosed by chance, for example, during a medical examination.
Several methods are used to make an accurate diagnosis, but the most relevant and accurate of them is special testing.
Tests
There are two types of tests that are used most often - the Rabkin and Yustova tests.
The patient is shown the same pictures in different lighting conditions, alternately shown a source of the same color to each eye in turn, and presented with pseudo-isochromatic tables and color ranking tests.
With various forms of color blindness, a person may not be able to distinguish colors, shades, saturation, and contrast. To clarify the result, other tests can be performed: the 15-shade Farnsworth panel test, its Lanthony modification, the 28-shade Roth test, and the 100-shade Farnsworth-Munsell test.
Color blindness glasses
The principle of color blindness glasses is that they dim bright light, since the cones are more sensitive in dim lighting. These corrective glasses look like regular tinted glasses, but are additionally equipped with shields on the sides.
The latest developments include glasses with high-tech multi-layer lenses, created in the USA. Such optics can almost completely eliminate mild forms of pathology and restore a person’s ability to distinguish between the colors of the red and green spectrum.
EnChroma has achieved outstanding success in the field of color perception correction. Initially, her profile was research into the possibilities of creating professional equipment for surgeons. Visors should sharpen color vision, helping the doctor during surgery. EnChroma's colorblind technology is designed to transmit and enhance primary colors, while blocking shades that impair color perception.
Cyanopsia
This is a pathology in which a person sees everything in blue tones.
This is a very rare pathology, always acquired. It occurs when the eye is injured, most often after removal of the lens, so many short light rays hit the retina. This makes it very difficult to perceive red and green shades. It can also occur due to inflammation in the retina. It happens that a person’s color perception is also reduced, and visual acuity is low.
Color blindness and driver's license
The difficulties that colorblind people encounter while driving, and the danger of such a situation for others, were first noticed in 1875. Then there was a railway accident in Sweden. During the trial, it turned out that the driver responsible for the incident suffered from color blindness and did not see the color red. Since then, a color blindness test has become a mandatory condition for obtaining a permit to drive a vehicle. The photo below shows how a person suffering from various color perception disorders sees a traffic light.
Today in the European Union, people with impaired color vision have the opportunity to obtain a driver's license on an equal basis with everyone, but cannot work in the field of commercial transportation or as public transport drivers. The situation is similar in the Russian Federation: a colorblind person can get a license of category A or B, but it will be noted that he does not have the right to work as a driver. In some countries, for example, Romania and Turkey, colorblind people are prohibited from driving.
Is there prevention?
Prevention makes sense only in relation to acquired forms of color blindness, and it is associated with maintaining a healthy lifestyle and the usual techniques for maintaining eye health:
- regular examination by an ophthalmologist;
- giving up bad habits (smoking, drinking alcohol);
- consumption of foods rich in vitamins and microelements;
- moderate physical activity;
- compliance with precautions in conditions of injury risk;
- maintaining personal hygiene;
- moderate distribution of eye strain.
People of any age need preventive visits to an ophthalmologist. Some eye diseases appear in childhood, while others (cataracts in particular) occur with age-related changes. This is why everyone needs to visit a doctor at least once a year.
Useful video
How people with different forms of color blindness see the world:
What difficulties do colorblind people face?
In society, approximately 7-9% of people have some kind of color perception disorder. In addition to restrictions on driving vehicles, they are subject to a number of prohibitions related to their choice of profession. Colorblind people cannot work as chemists, surgeons, pilots, sailors, and some military specialties are closed to them.
In everyday life, a person is surrounded by a huge number of color signals. And in this case we are not talking about traffic lights, since they are uniform, and colorblind people simply remember that the light of the top bulb means the need to stay in place, and the bottom one - to move forward. There are a lot of signs, signs and indicators that make life difficult for people with impaired color vision.
These days, more and more attention is being paid to the specific needs of colorblind people. Some websites and mobile applications make an additional version for the visually impaired; recently, versions adapted to the color perception of colorblind people have begun to appear. Digital content creators ensure that the color combinations used are comfortably perceived by users with various vision pathologies.
Is it possible to cure color vision impairment?
Treatment of color blindness is a very complex issue; pills for impaired color vision have not yet been invented, so it is not yet possible to completely get rid of the disorder. There is an option for correction using special glasses with complex lenses. You can learn more about the treatment of color blindness by watching the following video:
Prognosis and prevention
I am colorblind - this is not a diagnosis, but, most likely, a special view of the world. Don’t be shy about it, take advantage of the opportunity to correct your vision, look at the world with different eyes.
Additionally, we recommend reading the article about glasses for color blindness.
Prevention of this disease consists of checking genes for color blindness when planning a child, as well as a careful, respectful attitude towards one’s own health to avoid the acquired form of the disease.
